Steam-boiler.



, UNITED STATES PATENT OFFICE."

JOHN A. STEVENS, OF LOWELL, MASSACHUSETTS.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 660,660, datedOotober 30, 1900.

Application filed January 31, 1900. Serial No. 3,406. (No model.)

To aZZ whom it may concern:

Be it known that 1, JOHN A. STEVENS, residing at Lowell, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Steam-Boilers, of which the following is a specification.

These improvements relate to tubular steamboilers having superheating attachments and furnaces therefor.

An object of my invention is to provide a system of baffling so arranged that the passages through which the heated products of combustion travel on their Way from the furnace to the stack are gradually reduced in order that as their volume decreases, owing to the decrease of temperature, their distribution over the area of heatingsurfaces in such passages will be equalized.

A further object of my invention is to arrange the bafies and direct the heated products of combustion so as to avoid short-circuiting or cutting out of the track of the heated gases portions of the heating-surfaces.

A further object of my invention is to provide an improved form and arrangement of superheater adapted to be either used or dis- "connected from the system.

Other advantages resultingfrom my improvements will appear from the following detailed description.

In the accompanying drawings, Figure 1 is a longitudinal sectional view of a boiler, illustrating my improvements, taken on the line a a, of Fig. 2. Fig. 2 is a transverse sectional view thereof, taken on the line b b of Fig. 1. Fig. 3 is a transverse partial sectional View taken on the line of the fire and ash doors of the grate chambers. Fig. 4 illustrates a modified form of superheating apparatus which may be employed. Fig. 5 is a plan view of the superheater-drum and its connections. Fig. 6 is a view illustrating the connection between the water-boxes in the division-wall and the steam-and-water drum. Fig. 7 is a sectional view of a preferred form of cap for the headers.

In the drawings the primary passes or combustion-chambers 1 1 are separated by a division-wall 2, comprising in its construction water-boxes 3 and refractory tiles or bricks 4, which extend upward from the hollow base 5 to the roof-baflie 6, the division-wall separating the grates 7 7 and their respective combustion -chambers. The respective grates and grate-chambers or primary passes extend from this division-wall, to the containing- Walls 8 8, which inclose the water-boxes 9 9 and the refractory tiles or bricks 1O 10 supported upon the hollow bases 11 11. The refractory tiles 12 12' are used to reduce the grate area either in one combustion-chamber or both when the boiler is operated for maximum economy, and are taken out and the fire spread over the whole grate area when the maximum power of the generator is demanded. In case of forced draft the channels or air-ducts 5, 11, and 11', connected with the space beneath the grate, as by the openings 41, are employed for conducting the blast thereto.

The Water-box headers 13 13 connect the respective ends of the water-boxes 3 and are connected by the tubes 14 14. with the steam and-water drum 15 and the horizontal Waterbox 16, respectively, the drum 15 and the wator-box 16 being connected by the tubes 17, which'support the roof-baffle 6. A blow'off pipe 13 is connected with the header 13. The Water-boxes 9 9' are connected With the steam-and-water drum 15 and the horizontal Water-box 16 by the end headers 19 19. The steam generating tubes 18 18 have their respective ends connected by the sectional headers 19 19'. The headers 19 are connected directly with the drum 15 and are provided at their bases with the studs 20, which are received by the apertured supporting plate 21. A mud-d rum 39, located above the fire-doors 4.1, is connected to the front headers by the nipples 38. The headers 19 are connected directly with the water-box 16 and are supported upon the chairs or struts 22 and are free to slide upon the plates 23 in compensating for expansion or contraction. The struts 22 also sustain the refractory wall 24 at the rear of the primary combustionchambers.

The horizontal baifies 25 25 and the diagonal bafifles 26 26 of the primary pass or combustion-chamber are sustained by the tubes 18 18. The diagonal baffles 27 27 of the secondary passes and the horizontal bafiles 28 .1 28 of the tertiary passes are sustained in like manner. The arrangement of these bafl'les is such that the heated products of combustion are always carried in directions transverse to the steam-generating tubes through .constantly-contract-ing passages so disposed as to afford, easy circulation for the gases and avoiding short-circuiting.

In the upper region of the primary and secondary passes are placed tubes 29 29, 'pref- 1 'erably coiled, as illustrated in Fig. 2, which connect the steam-and-water drum with the s'uperheater-d rum '30. The superheatingtubes are made in separable parts and joined by a coupling 29 in order that the part beneath the roof-baffie, subjected to great heat,

when they are closed. Steam is drawn ed from the superheater-drum by means of the take-0E 32 and water by means of the valved drain-pipe 33. The steam-and-Water drum is provided with a steam-baffie 34, closed at both ends, affording communication between the steam-space of the steamand-water drum and the tubes 29 through the aperture 35 at the top of the drum. 1 The steam-and-water drum is also provided with the dry-pipe 36 and the take-off 37, which may be used for taking off steam when the superheater is omitted or for a safety-valve mounting when the superheater is used.

In the construction of the caps 42 for the headers the cap proper, 43, fitted with the joints 44 and 45, which receive annular ringpackings, is held to the opening 46 through the header by a bolt 47, which passes through the washer 48 and is drawn up by the hooded nut 49.

In operating the boiler Water is admitted by the feed-pipe 15 to the steam-and-water drum 15, whence it flows through the watercirculating and steam-generating system by way of the downcomers or headers connected therewith. As steam collects in the upper half of this drum it is compelled to travel to the extreme top thereof in order to escape above the steam-bafile 34 to the superheatingtubes 29 29, through which it passes to the superheater-drum 30, whence it is drawn off.'

As the passage of the steam through the superheating-tubes carries it through a very hot part of the combustion-chambers, Where it has greater or less dwell, particularly in the construction of tubes illustrated in Fig. 2, the steam taken from the superheaterdrum is in a highly dry and superheated condition.

The arrangement of the baffles for the gratechamber and primary pass enables the grate to be extended beneath all of the passes of the combustion-chamber of each division of the furnace, affording a Very large grate area as compared with the space taken up. By

using the diagonal spaces between'the tubes for sustaining the diagonal baliles economical supports are provided, and the arrangement of the baffles effects the concentrationof the heated products of combustion and provides an easy course for conducting the gases into active contact With the gradually-contracting area of heating-surface as they pass from the primary combustion-chambers between the primary baflies and the secondary baffles and between the secondary and tertiary baffles to the funnel. i

The ability to use either one or both compartments of the furnace to adjust the grate area or areas, to adjust the bafiies supported by the water-circulating and steam-generating tubes, and to remove the superheatingtubes renders the regulation and repair of the boiler and furnace advantageous in a marked degree.

Having thus described my invention, 1 claim 1. In a steam-boiler, a steam-and-water drum, a superheater-drum, a series of superheating-tubes connecting said drums, and a valved floodingrpipe connecting said drums, substantially as specified.

2. In a steam-boiler, a steam-and-water drum, a superheater-drum substantially parallel thereto, a series of sectional superheating-tubes connecting said drums, and a valved flooding-pipe connecting said drums, substantially as specified.

3. In a steam-boiler, a steam-and-Water drum, a superheater-drum, a series of super heating-tubes leading from said steam-andwater drum to said superheater-drum, and a baffle for compelling steam to travel to the top of said steam-and-water drum in passing to said superheating-tubes.

4. In a steam-boiler, a combustion-chamber, a roof-baffie therefor, a steam-and-waterdrum, asuperheater-drum, and superheatingtubes passing through said roof-baffle and leading from said steam-and-water drum to said superheater-drum.

5. In a steam-boiler, a combustion-chamher, a roof-baffle therefor, a steam-and-Water drum, a superheater-drum, a series of superheating-tubes passing through said roof-baffle and connecting said drums, a valved flooding-pipe connecting said drums, and a valved drain-pipe leading from said superheaterdrum.

6. In a steam-boiler, a combustion-chamber, a roof-baffle therefor, a steam-and-water drum, asuperheater-drum, and superheatingtubes connecting said drums, said tubes extending above and below said roof-baffle and having coils in said combustion-chamber.

7. In a steam-boiler, a combustion-chamber, a roof-baffle therefor, inclined baffles for said combustion-chamber, a steam-and-water drum a superheater-drum, and superheatingtubes connecting said drums, said tubes passing through said combustion-chamber and said baffles concentrating the gaseous prodnets of combustion and directing the same transversely to said tubes, substantially as specified.

8. In a steam-boiler, a pair of combustionchambers, a roof-bafiie therefor, inclined baffles in each of said combustion-chambers for concentrating and directing the fuel products in passing therethrough, and superheat-ingtubes passing through each of said combus- I0 tion-chambers, said baffles concentrating the gaseous products of combustion and direct ing the same transversely to said tubes, substantially as specified.

In testimony whereof I have hereunto set my hand, in the-presence of the subscribing r 5 Witnesses, this 27th day of January, 1900.

JOHN A. STEVENS.

Witnesses:

PHILIP R. COATS, GEORGE M. STEVENS. 

